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Bose 901 VI, havent found the right amp - Page 7

post #181 of 201
Quote:
Originally Posted by JerryLove View Post

Indirect lighting is certainly not uncommon.

And heavy use of reflected sound is something you'll find in a lot of designs (Ohm, Martin Logan, Magipan, half of everyone's surround speakers, etc). I'm not defending the 901, but the premise that reflected sound can add positively to the experience is reasonable.

And I'm not sure of how they do the crossover: but since their drivers are about big enough that a single one could do midrange; it's possible that the wall-facing drivers are mainly for LF extension.

I'm pretty sure that the 901s have no crossover. The identical drivers cover the same frequency range. From what I read elsewhere, the nine drivers in aggregate average out the random resonances that each individual driver produces, helping to produce a more even response curve.

Now the spectral information that the reflecting speakers produce are not lost in rooms with reflecting surfaces, but are presented with delays relative to the direct facing driver output. So your ears essentially receive all the sound energy, with minute delays. The direct driver (essentially without delays) provides sound localization.

You would only lose the reflected energy if absorptive materials are used in the room.

In the case of indirect light if you use enough light energy you can read by indirect light (unless dark surfaces are absorbing it), but essentially in most circumstances you want a narrow beam focused on the page. Compared to the eyes, the ears are faced outwards picking up sound from a much wider area, so the total acoustic energy is received and interpreted even when the majority of it is indirect (reflected)..
Edited by taichi4 - 2/18/13 at 6:04pm
post #182 of 201
Quote:
Originally Posted by taichi4 View Post

I'm pretty sure that the 901s have no crossover. The identical drivers cover the same frequency range. From what I read elsewhere, the nine drivers in aggregate average out the random resonances that each individual driver produces, helping to produce a more even response curve.
I'd be worried about very basic stuff: like comb filtering.
Quote:
Now the spectral information that the reflecting speakers produce are not lost in rooms with reflecting surfaces, but are presented with delays relative to the direct facing driver output. So your ears essentially receive all the sound energy, with minute delays. You would only lose the energy if absorptive materials are used in the room.
Most materials absorb in some frequencies.
Quote:
In the case of indirect light if you use enough light energy you can read by indirect light (unless dark surfaces are absorbing it), but essentially in most circumstances you want a narrow beam focused on the page. Compared to the eyes, he ears are faced outwards picking up sound from the a much wider area, so the total acoustic energy is received and interpreted even when the majority of it is indirect (reflected)..
The building I work in is lit with indirect lighting. It's an office.

My family room is also indirect (those 300w halogens you can buy at Walmart... direct would be literally (if temporarily) blinding.
post #183 of 201
Quote:
Originally Posted by JerryLove View Post


...Most materials absorb in some frequencies.
The building I work in is lit with indirect lighting. It's an office.

My family room is also indirect (those 300w halogens you can buy at Walmart... direct would be literally (if temporarily) blinding.

As I mentioned, indirect lighting, if the total amount of light output is high, will light up a page as much as a less radiant, but focused light source. I'm no enemy of indirect lighting!

If a room has hard reflecting surfaces little sound energy is absorbed.

A quick net search:

"For this reason, acoustically minded builders of auditoriums and concert halls avoid the use of hard, smooth materials in the construction of their inside halls. A hard material such as concrete is as dissimilar as can be to the air through which the sound moves; subsequently, most of the sound wave is reflected by the walls and little is absorbed. "

http://www.physicsclassroom.com/Class/sound/U11L3d.cfm

Regarding the comb filter effect comment, I was just addressing your remark by pointing out that the 901s do not use crossovers, not discussing the potential negative effects of systems employing a high degree of reflection.

However. comb filter effects are likely reduced by positioning the 901s close to the walls (as Bose recommends), because you are thereby introducing less complex reflections, minimizing the reinforcement and cancellation effects that produce the comb filter phenomenon.
Edited by taichi4 - 2/18/13 at 6:42pm
post #184 of 201
Quote:
Originally Posted by taichi4 View Post

However. comb filter effects are likely reduced by positioning the 901s close to the walls (as Bose recommends), because you are thereby introducing less complex reflections, minimizing the reinforcement and cancellation effects that produce the comb filter phenomenon.
Comb filtering is unavoidable when two drivers have part of their surface more than 1/4 wavelength of a frequency they are both producing (unless they have an almost complete lack of off-axis output, or there's a baffle in excess of 1/4 wavelength in between (or is that 1/2 wavelength)).

A *lot* is done in crossovers and speaker design for line arrays to reduce this effect.
post #185 of 201
Quote:
Originally Posted by JerryLove View Post


Comb filtering is unavoidable when two drivers have part of their surface more than 1/4 wavelength of a frequency they are both producing (unless they have an almost complete lack of off-axis output, or there's a baffle in excess of 1/4 wavelength in between (or is that 1/2 wavelength)).

A *lot* is done in crossovers and speaker design for line arrays to reduce this effect.

Understood, but crossovers introduce their own problems.

Now a speaker design like the Walsh full range driver is crossover-less, and doubtlessly produces cancellation and reinforcement effects, as it radiates omnidirectionally, but in my experience sounded better than any other speaker I've ever heard.
post #186 of 201
Quote:
Originally Posted by taichi4 View Post

Understood, but crossovers introduce their own problems.
So do contour networks. Rule #1 of acoustical engineering is that there's no such thing as a free lunch. What the Bose gains by having no crossover it gives back with the necessity of a contour network, and the narrow HF dispersion that results from having no tweeter. Comb-filtering doesn't occur with the 901, as the eight drivers that do comb-filter are facing the wall, but the downside there is the vague imaging that also results from so doing.
post #187 of 201
Quote:
Originally Posted by Bill Fitzmaurice View Post

So do contour networks. Rule #1 of acoustical engineering is that there's no such thing as a free lunch. What the Bose gains by having no crossover it gives back with the necessity of a contour network, and the narrow HF dispersion that results from having no tweeter. Comb-filtering doesn't occur with the 901, as the eight drivers that do comb-filter are facing the wall, but the downside there is the vague imaging that also results from so doing.

Once again, no argument.

My speaker of choice is the Walsh design, followed by BMRs (balanced Mode Radiators).
post #188 of 201
Quote:
Originally Posted by taichi4 View Post

Understood.

Hail Alberta, Canada...and Canada in general. I've always had a good time there...as far East as Nova Scotia,
and West as Toronto (not far west). Now I live in LA, yet have never been up to Western Canada. wink.gif

How's the healtcare plan in Alberta?

It must suck to be stuck in California:)

Sound like You pay attention to Politic abroad.
The richest Province in Canada and pay the most in healthcare and only get half the services of other Provinces.
I do not have a problem as far of services, but way too much money spend on managment.

Now back to Audio topics.

All the best.

Ray
post #189 of 201
Quote:
Originally Posted by taichi4 View Post

Quote:
Originally Posted by JerryLove View Post


Comb filtering is unavoidable when two drivers have part of their surface more than 1/4 wavelength of a frequency they are both producing (unless they have an almost complete lack of off-axis output, or there's a baffle in excess of 1/4 wavelength in between (or is that 1/2 wavelength)).

A *lot* is done in crossovers and speaker design for line arrays to reduce this effect.

Understood, but crossovers introduce their own problems.

Now a speaker design like the Walsh full range driver is crossover-less, and doubtlessly produces cancellation and reinforcement effects, as it radiates omnidirectionally, but in my experience sounded better than any other speaker I've ever heard.

Amen to that! The thing is, everyone is so conditioned by the ubiquitousness, if that's a word:) of crossovers and multi-band speaker systems that their deleterious effects are not even noticed. They are just accepted because most people don't hear any alternatives.

I had the opportunity a number of years ago to buy a mint, used pair of Ohm F's for $400. I passed, and have regretted it many times since.
post #190 of 201
Quote:
Originally Posted by dat56 View Post

Amen to that! The thing is, everyone is so conditioned by the ubiquitousness, if that's a word:) of crossovers and multi-band speaker systems that their deleterious effects are not even noticed. They are just accepted because most people don't hear any alternatives.

I had the opportunity a number of years ago to buy a mint, used pair of Ohm F's for $400. I passed, and have regretted it many times since.

The good news is that even if Ohm is no longer making full range Walsh speakers, HHR Exotic is. Not only are they fabricating them, they are also carefully rebuilding Ohm full range Walsh systems. something Ohm no longer offers.

I had never heard of HHR until, spurred by this discussion, I searched for articles and posts about crossoverless systems, and about my favorite concept...the Walsh driver. By the way, Lincoln Walsh, the creator of this driver, was involved with developments in the early days of radar. I guess that made him think about waves in sound reproduction.

When I heard the Ohms the speakers did disappear, and the soundstage hung in the air so transparently and clearly. And this just goes to show how concepts about sound reproduction and real world experience may differ. I had convinced myself that speakers should, as much as possible, minimize reflection, but the Walsh driver radiates omnidirectionally. And yet, I have never heard anything as good.

As for that $400. !!!!!! But we all have stories like that.

And yes, ubiquitousness is a word, and a very good one at that!
Cheers
post #191 of 201
Quote:
Originally Posted by darthray View Post

It must suck to be stuck in California:)

Sound like You pay attention to Politic abroad.
The richest Province in Canada and pay the most in healthcare and only get half the services of other Provinces.
I do not have a problem as far of services, but way too much money spend on managment.

Now back to Audio topics.

All the best.

Ray

Before we return to the subject at hand, which Province has the best healthcare system?

As far as California is concerned, you have been here and experienced the weather? wink.gif
post #192 of 201
Quote:
Originally Posted by taichi4 View Post

As far as California is concerned, you have been here and experienced the weather?
You mean the one thing that isn't taxed...yet? smile.gif
post #193 of 201
Quote:
Originally Posted by dat56 View Post

Amen to that! The thing is, everyone is so conditioned by the ubiquitousness, if that's a word:) of crossovers and multi-band speaker systems that their deleterious effects are not even noticed. They are just accepted because most people don't hear any alternatives.

I think in the first world the majority of people that would actually discuss audio have heard headphones before (which are single-driver crossoverless speakers). I am dubious of your premise.
post #194 of 201
Quote:
Originally Posted by taichi4 View Post

Before we return to the subject at hand, which Province has the best healthcare system?

As far as California is concerned, you have been here and experienced the weather? wink.gif

I would say Quebec, British Colombia, Ontario and now Sakachawan.

Not in many years, but California is nice and warm, not snow day after day.


Ray
post #195 of 201
I have a bit of a rarity in Canada. On Vancouver Island, I have a nice 20 foot windmill palm tree in my front yard that I planted close to 20 years ago when it was only 2 feet tall. It is quite happy in its location & continues to flower & send out more fronds every year. Obviously it must like lots of water - and we have lots of that in winter up here, ha!

As for healthcare, it's great except for the fact that it is bankrupting us both as a Province & a Country. Our friends to the south are about to find that out as well...

TAM
post #196 of 201
Quote:
Originally Posted by ex-labdriver View Post

As for healthcare, it's great except for the fact that it is bankrupting us both as a Province & a Country. Our friends to the south are about to find that out as well...

I can't decide whether it's worse for us to go individually bankrupt paying the insurance companies and then paying medical bills anyway because things are not covered, or going bankrupt as a nation for essentially the same reason.
post #197 of 201
Get our stupid govt out of the equation and watch prices go down.
post #198 of 201
really guys? So off-topic
post #199 of 201
Quote:
Originally Posted by JerryLove View Post

really guys? So off-topic

Not entirely.

If I had more free cash left after paying my health insurance bill, I could afford some nice new speakers. wink.gif
post #200 of 201
Quote:
Originally Posted by JD in NJ View Post

If I had more free cash left after paying my health insurance bill, I could afford some nice new speakers. wink.gif

Time to move to the country with the lowest per-capita healthcare costs then. I believe that's Germany.
post #201 of 201
Quote:
Originally Posted by JerryLove View Post

Time to move to the country with the lowest per-capita healthcare costs then. I believe that's Germany.

I've only been there once, and enjoyed it very much.
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